All those iPhone 4S users planning to unlock their iPhone 4S in near future should stay at iOS 5.0. The latest blog post, MuscleNerd clearly mentions that iPhone 4S running iOS 5.0 have higher chances of getting an unlock in near future…

To maximize chances of iPhone 4S software carrier unlock, iPhone 4S users should stay at iOS 5.0, says MuscleNerd. All those users iPhone 4S users who have updated to iOS 5.0.1, it’s too late to go back to 5.0. However, it might not be too late to downgrade baseband by going to 5.0.1 build 9A405 from 5.0.1 build 9A406, since an unlocking method will most likely be found for the older build first.Check your 5.0.1 Build and downgrade to older one (it’ll downgrade baseband to older build too). Do it While Apple is signing both the builds. You can find direct firmware links here: Download iOS Firmware.

This what MuscleNerd mentioned in his latest blog post:

iPhone4S owners looking to maximize their chances of achieving an eventual software-based carrier unlock should be staying at 5.0. Everyone else should be at 5.0.1. If you’re an iPhone4S owner who already updated to 5.0.1, it’s too late to go back down to 5.0, but if you’re on iPhone4S owners looking to maximize their chances of achieving an eventual software-based carrier unlock should be staying at 5.0. Everyone else should be at 5.0.1. If you’re an iPhone4S owner who already updated to 5.0.1, it’s too late to go back down to 5.0, but if you’re on 9A406 it is possible to downgrade the BB by going to the 9A405 version of 5.0.1 while the window is still open. it is possible to downgrade the BB by going to the 9A405 version of 5.0.1 while the window is still open.

So, to ensure the greatest possibility of unlocking your iPhone 4S, stay with 5.0 and avoid iOS 5.0.1. It is standard operating procedure to stay at the lowest possible baseband. The iPhone 4S unlock is expected to be released soon after the Corona A5 (iPhone 4S and iPad 2) jailbreak public release. checkout: Corona A5 jailbreak Important details.